A SI- or subscriber identity module, abbreviated as SIM, is an electronic component (typically in the form of a card) comprising for instance an integrated circuit which contains information relating to the identity of, e.g. a subscriber in a telephone system. The subscriber identity module comprises contact areas (short: card contacts) which form a contact pattern, which typically corresponds to the contact pattern of an IC (integrated circuit)-card (chip card) in accordance with the ISO standard 7816. However, the outer dimensions of the SIM card are substantially smaller than the outer dimensions of a chip card, i.e. 25 mm.times.50 mm for the SIM and 85,5 mm.times.54 mm of the chip card.
It is an object of the present invention to provide a contacting apparatus for a SIM (the term SIM will be used interchangeably with the term SIM-card), such that the outer dimensions of said contacting apparatus are only insignificantly larger than the dimensions of the SIM itself. Preferably, the thickness of the contacting apparatus should preferably be smaller than 3 millimeters.
It is another object of the present invention to provide a contacting apparatus for a SIM such that the contacting forces which are provided by the contact elements of the contacting apparatus are the same or larger than the contacting forces provided by the contact elements of a contacting apparatus for the larger chip cards.
In accordance with a further object of the present invention a switch is provided in the contacting apparatus which closes or opens as soon as the contact elements (the so-called reading contacts) of the contacting apparatus touch upon said contact areas of the SIM located in its reading position in the contacting apparatus.
In accordance with a still further object of the present invention the contacting operation between the contact elements of the contacting apparatus and the contacts of the SIM should be made for certain applications without relative movement between the contacting apparatus (reader) and the SIM card.
A contacting apparatus for customary chip cards is known, but either its length or its height goes beyond the desired dimensions. This is due to the fact that without a limitation of the outer dimensions the same contact forces between 0.2 and 0.4N (Newton) are required. Due to the limitations of contacting forces and spring movement or spring path (comprising the tolerances of the thickness of the card and the preciseness of manufacture) spring elements for the contacting apparatus result which will, if arranged in the traditional way, cause that the above mentioned desired dimensions are exceeded.
The present invention provides for a contacting apparatus obviating the above mentioned disadvantages. The contacting apparatus of the invention is particularly useful for contacting a SIM card, but can be used with a chip card, resulting in very short chip card contacting apparatus.
In accordance with one aspect of the invention the contacting apparatus comprises contact elements which are arranged such that the contact pitch (contact spacing) is cut in half and the length of the contacting apparatus is reduced by the distance of the rows of the contacts of the SIM.
Preferably the contact springs of the contact apparatus for one row of SIM contacts are located between the contact springs for the other row of SIM contacts. Preferably, a cover of the contacting apparatus can be designed to act as a SIM holder, i.e. as a means to hold the SIM in its so-called reading position in the contacting apparatus.
A field of application for the SIM-contacting apparatus of the invention is for so-called mobile telephones. In this example the contacting apparatus is installed into said mobile telephone. As soon as a user has inserted a SIM card into said contacting apparatus and into the reading position, information regarding the subscriber can be read out of said SI module by means connected to said contact elements.
In accordance with another aspect of the invention a chip key as shown in the journal "Design und Elektronik" of Jan. 23, 1990 published in Germany is improved. Said known chip key may contain a SIM which will be contacted when the key is used in a respective contacting apparatus. In this known arrangement the card forming or supporting the SIM is subject to dirt so that high contacting forces are required. Such high contacting forces are not suitable for high contacting cycles. By using the contact elements of the invention, said disadvantage can be overcome. Preferably, the connections or termination ends of said contact elements are designed as second contact locations. In this form the contact element can be inserted into a key connector of the type C701 of Amphenol-Tuchel Electronics GmbH, Heilbronn, Germany. Thus the following advantages are achieved:
The card is covered and thus protected; the contact location which is independent of the card contact is designed for continuous use.